Smoke (sometimes called "fog") has been a tool of the entertainment industry for decades for creating atmosphere as well as for making lighting effects more visible. For this reason smoke has found extensive use in the theater, movies, rock concerts, commercials, nightclubs and discotheques. In the past the fluids used in commercial smoke generators produced a chemical smoke which, while aesthetically satisfactory, created safety problems such as slippery floors, toxicity and fire. However, with the more recent advent of water-based and non-toxic glycol-based chemical smoke producing fluids the use of smoke generating machines in the entertainment industry has grown at an incredible rate.
Chemical smoke or fog generating machines produce, for the most part, smoke-type fog which hangs in the air and is particularly useful for creating effects such as smoke in battle scenes or the atmosphere of a large smoke filled room. Chemical smoke or fog is also very useful as a dispersion media to create interference for the optical viewing of collimated and non-collimated light. However, chemical smoke or fog is not effective for producing a low lying fog effect, i.e., a low lying cloud which dissipates as it begins to rise, such as an atmospheric mist hovering close to the ground. Heretofore, the low lying fog effect was created by use of dry ice foggers wherein the dry ice vapors themselves created the low lying mist. Although effective for this purpose, such mists present a potentially lethal hazard, particularly in small enclosed spaces, because dry ice mist is made up of carbon dioxide which may interfere with the availability of oxygen for breathing. Moreover, a special dry ice fogger is required so that separate generators must be available depending on the type of fog effect desired. In addition, dry ice is difficult to obtain, hazardous to handle and expensive to use.